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Proof Beyond a Reasonable Doubt That Majorana Fermions Exist

Not only could they transform quantum computing, they’re a candidate for dark matter.

A team of Chinese physicists from Shanghai’s Jiaotong University have proof beyond a reasonable doubt of the existence of the Majorana fermion — a special particle that could potentially revolutionize quantum computing.

"The search for this particle is for condensed-matter physicists what the Higgs boson search was for high-energy particle physicists," said Leonid Rokhinson, an associate professor of physics at Purdue University, who was the first to detect the signature of the fermion in 2012 but was not involved in this study, in a 2012 press release. "It is a very peculiar object because it is a fermion yet it is its own antiparticle with zero mass and zero charge.”

For the first time, the spin properties of Majorana particles were observed. "The Majorana fermions has several properties. Like zero energy, spin property and special distribution. In our case, we observed all the features of Majorana fermions. So we are more confident," Professor Jia Jinfeng from Shanghai Jiaotong University and co-author of the paper, told CCTV News.

Why are Majorana fermions important? They can solve a problem quantum computing currently faces. Current carriers of quantum bits — the basic unit of information in quantum computing — are easily destroyed by small disturbances from the local environment, such as magnetic interferences. However, information stored using Majorana fermions are protected from such changes, resulting in more resilient quantum computing.

But their impact doesn’t end with quantum computing.

"It is significant from two aspects. One from the fundamental physics standpoint. Due to its peculiar character, it is considered a potential candidate for dark matter to help us to know more about the universe. And because of their minimal interaction with the rest of the world, they could also help scientists to build quantum computers," said Zhang Ze of the Chinese Academy of Sciences and co-author of the paper.

In 2012, the signature of the fermion was observed using the Josephson effect, which describes how an electrical current traveling between two superconductors oscillates at a frequency dependant on the voltage. In the presence of Majorana fermions, the frequency-voltage relationship changes by a factor of two. The effect is very unusual and specific to the Majorana particles. But it is not the easiest method to detect the particles.

Luckily, the new technique developed by the Chinese physicists, which involves sandwiching insulators and superconductors, provides a more straightforward way to observe the elusive fermions.